This invention relates to an evacuated insulation panel having a corestock of an open-cell alkenyl aromatic polymer foam. The foam has indentations therein to provide a panel having aesthetically desirable, non-wrinkled surfaces.
To significantly improve the performance of insulating systems, evacuated or vacuum panel technology is currently being evaluated by industry. The removal of substantial amounts of air or gas in the panels affords the possibility of superior insulating performance.
A useful evacuated panel is one employing a panel corestock of a rigid open-cell alkenyl aromatic polymer foam. The open-cell structure of the foam allows rapid and substantially complete withdrawal of gases from within the foam and the panel containing it. The rigid foam matrix provides a corestock of substantial mechanical strength and insulating performance.
A problem with employing panel corestocks of open-cell alkenyl aromatic polymer foams is their tendency to shrink upon being evacuated and/or being exposed to elevated temperatures. The shrinking may result in a wrinkled surface appearance for the receptacle or enclosure maintaining a hermetic seal in the panel.
It would be desirable to have an evacuated insulation panel with a corestock of an open-cell alkenyl aromatic polymer foam. A surface or surfaces of the panel would exhibit an aesthetically desirable, relatively smooth and homogeneous surface substantially free of wrinkles or ridges. It would be desirable to produce panels having a substantially flat surface so that the insulating panel can be placed or situated flush or adjacent to flat, smooth surfaces such as the inside of a refrigerator wall.